The effects of ear protectors and hearing losses on sentence intelligibility in aircraft noise

Flight line personnel with hearing defects often complain that face-to-face speech communication in noise is considerably reduced when ear protectors are worn. Whether this could be confirmed or not was determined. An effective noise protecting flight helmet changes the flat aircraft cabin noise spectrum into a spectrum with predominance of lower frequencies. Whether the additional wearing of earplugs under the ear cups might improve speech perception was investigated.